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Bizarre PSU Behavior

Discussion in 'Power Supplies' started by Desaan, Jun 19, 2017.

  1. Desaan


    Joined: Jul 15, 2009

    Posts: 44

    Location: Liverpool, UK

    Corsair AX860 PSU

    This started a few weeks ago with my PC failing to power on from a cold boot, motherboard LED's et al functioning but it wouldn't even attempt to POST. So after checking every single cable, reseating everything, double checking everything I could find nothing wrong whatsoever. Then in a lazy attempt to flick with PSU power switch on I kind of put it in a neutral position before if flicked back to on and the bloody PC started, past POST straight to windows, everything running fine.

    So I powered it down again and attempted to start it normally, wouldn't power on until I replicated the same messing with the PSU switch as earlier. Is this symptomatic of a faulty PSU or could something else MOBO related be causing it? The entire build is less than a year old (OCUK custom built) and I don't think I've experienced an issue like this ever before. Sadly I don't have PSU of similar power/quality to test it against so I'm at a loss.

    i7 5820k 4.0ghz
    16GB Kingston Quad Channel DDR4 @2400mhz
    Strix X99 Gaming Mobo
    Nvidia GTX 1080 GPU
    Corsair AX860 PSU
    Samsung SM951 128GB M.2 PCI-e Gen3 8Gbps (OS)
    Samsung 500GB 850 EVO SSD
    4TB Storage Drive
    Asus Xonar DX 7.1
    Corsair Hydro H105 240mm CPU Cooler
    Windows 10 x64 Home
  2. EsaT


    Joined: Jun 6, 2008

    Posts: 2,938

    Location: Finland

    Even 500W PSU would be easily enough for testing if it boots properly without problems.

    For one thing you could try clearing CMOS (or removing overclock manually) to get default clocks to see if that changes things.
  3. mattyfez


    Joined: Apr 12, 2007

    Posts: 7,835

    Sounds like the PSU switch is faulty, maybe a dry solder or something.

    It'll be under warranty though so I'd get in touch with customer services rather than mess with it.
  4. Desaan


    Joined: Jul 15, 2009

    Posts: 44

    Location: Liverpool, UK

    Clearing the CMOS is one of the first things I did, unfortunately after doing so and restarting it just stays in a powered off state. The PSU is modular and I don't have any spare modulars about only the 'old' kind.

    It's dodgy as hell trying to turn it on but its fine once its up and running, think I'll just leave it powered on till I can sort out an RMA.
  5. pastymuncher

    Man of Honour

    Joined: Jul 12, 2005

    Posts: 15,878

    Location: Aberlour, NE Scotland

    Test the pc with a standard psu then. Even if you had a spare modular psu lying around you would probably blow something up if you plugged cables that were not it's own into it as different makes (and even oems within brands) use different pinouts. We have seen it happen several times on here.
  6. Desaan


    Joined: Jul 15, 2009

    Posts: 44

    Location: Liverpool, UK

    Got a replacement one today, all good now. Surprised by a Corsair PSU not even lasting 9 months.

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